Electrical connector



Aug. 27, 1946. Ys, N BUCHANAN 2,406,346

v ELECTRICAL VCONNECTOR Filed Sept. 11,l 1943 ATTO NEYS Patented Aug. 27, 1946 Stephen.N.-Buchanan, Washington, D. C., assignor to Aircraft-Marine Products, Inc., Elizabeth, N. .J., a corporation'of New Jersey Applicatiomseptember 11, 1943'Serial Nm 501,909.

1.0la`im. (Cl. 173-269) II-hisrinvention relates to cableconnectorsand more specifically to a connector which may ybe attached to an electrical conductor to effecta strong; low-resistance connection or `may at will be detachedtherefrom Without the useof special tools. 1

.The present invention isparticularly well suited to use with stranded electrical conductors or cables, but obviously its application is notlimited to conductors .of thestranded type. Heretofore electrical connectors for ,binding conductors of this type to :binding posts, terminalcontacts, and .the like, either have. required permanentlattach- .ment to the electrical conductors, as bybrazing or by soldering, or .else .they have involved a mechanicallocking or clampingactioncallingfor .the use of special tools and fixtures in order to make a sufficiently tight loond.,v The electrical connectors which were permanently ,attached ,to the electrical conductors could, l.or many purposes, be made sufliciently strong and to give an electrical bond of .low conductivity,y but they rsuffered the disadvantage that' once they were 'attachedythey permitted of no subsequent rearplicated or cumbersome to be of great practical value.

It is an object of the present invention to provide an electrical connector whereby an electrical conductor may be connected to an electric terminal in a practical manner and wherein the electrical connector may be disconnected from the electrical conductor easily and Without the use of special tools. Another object is the provision of a collet, as will be described, for use in establishing and maintaining an easily broken and rearranged electrical connection. Other objects will be in part pointed out as the description proceeds and will in part become apparent therefrom.

'Ihe present invention results from' the discovery that a collet, as will be described, may be positioned within a ferrule-like sleeve and that if one end of the collet projects through the sleeve and is threaded so as to receive a collet nut, and if the other end of the collet is properly slotted and configured with-an expandingthickness, @the colletmay be drawn into thesleeve bymeans of the collet nut with-a wedgingaction resulting from the expanding thickness at the-,opposite end of the collet. If the collet itself is first telescoped over thebareend of a-wire cable oran-y electrical lconductor before the collet nut `is tightened, the wedging actiony may be used. to eiect an excellent mechanical Aengagen'l-ent.and electrical contact .betweentheeollet.andtheelectrical conductor and to form as tight avbond as may be desired between the -electrical conductor and a binding post to which the electricaleonnector vmay be clamped. Moreover, Vany subsequent pullon the cable, etc., will tend, by wedging the collet more tightly into the sleeve, to vtighten its grip on the cable, etc.

In this specication and the accompanying drawing, I have shown and described a preferred embodiment of `my invention and lvarious modications thereof; b-ut it is to be understood 'that these are not intended to be exhaustive nor limiting of the invention, but on the contrary-are given for purposes of' illustration in order that others skilled in the lart may fully understand the invention and the principles thereof and the manner of applying it in practical use so .that they Vmaymodify and adapt it in various forms', each as may bebest suited to the .conditionsfof a particular use.v

In the accompanying drawing, in which t a satisfactory form of the inventionfor achieving the above objectives is set forth:

Figure 1 is an end elevation of a collet embodying the invention;

Figure 2 is a side elevation of thezcolletfshown in Figure 1;

Figure 3 is an elevation of the collet shown in Figure 1 but taken from the opposite end;

Figure 4 is a sectional elevation of the collet shown in Figure 2;

Figure 5 is an expanded perspective view of the collet shown in Figures 1 through 4 in association with a ferrule-like sleeve and collet nut and in accordance lwith the invention; Y

Figure 6 is a sectional elevation of the parts shown in Figure 5 in assembled relationship and clamped upon the end of an electrical conductor; 1

and

Figure 7 is an end elevation of the in Figure 6.

With reference to Figures 1 through 4, a collet l0 is shown having an externally threaded portion Il toward its right-hand end (see Figures 2 and 4) and being provided with a gradually inparts shown creasing diameter toward its left-hand end. The end of increased diameter is slotted, as at 26, and these slots (taper somewhat toward the longitudinal center of the collet so that they'are narrower toward their innermost points. The interior of the collet is serrated, as at 32, within its slotted, enlarged portion and each endv Of the cylindrically. shaped passage through the collet vis interiorly enlarged somewhat so as to afford a slightly ilared or funnel-shaped end. The left-- hand funnel-like inner enlargement of the collet (see Figures 2 and 4) is indicated at SBand af-` fordsa clearance for a purpose to be, described, The combination of slots 26' Withrthe increasing diameter and thickness of the Vferrule providesV -made in accordance Withthe instant invention and as above described is admirably suited for 'easy connection upon or disconnection from an Wedge-shaped segments 28 toward the left-hande I end of the collet as viewed in Figures 2 and 4.

Figure 5 shows collet I0 in association with a terminal connector 2E! provided with a ferrule 2 4 and a yCollet nllt I2. n rIYhe threaded'portion of colletY I0 Yis inserted through `ferrule 24 so that colletnut I2 may be'screwed onto the threads of the collet thus drawingcollet Illinto ferrule 24. Connector 20 is of thetype illustrated and claimedin the copending application of James O.

Johnson', Serial No. 484,167, iiled April 23, 1943. As pointedV out in said Johnson application, this connector advantageously is made from dead soft,

Ymalleable sheet copper.

Figures and? illustrate the manner in which the bared 'end I6 of a conductor I8 maybe telescoped Within colletl I0 in association with connector 20 and collet lnut I2, as' indicated in Figure 6, by tightening nut I2 upon the threaded portion of the collet. The wedge-shaped segments 28 are forced inwardly intointimate contact with the wire of the conductor by means of the wedging action effected by relative movement of the' collet with respect to ferrule v24. Tapered slots 26 'permit'the portions of greater thickness tobe compressed radially. Clearance 30 gives some relief at'the thicker portions of the segmenta'rbutY the dimensions of the c'ollet are such "that it is 1 impossibleY to draw the collet completely within ferrule 24. In one' satisfactory V form of the inventionthe cross-'sectional area of the central opening in the larger end of the collet, when :compressed as much as possible, is less t than the cross-sectional area of the central openingY in Vthe smaller end of 'the collet by about l5 to 20 per cent. The over-all area at the larger Vend may likewise be about to 20 per cent greater than that of the smallest part of thejhole'inthe ferrule. f .ji

The sharp edges formed by slots 26 are advantageous, in that they cut into the sidewalls of ferrule 24, and through any oxide lm thereupon,

. electrical conductor and that when connected a mechanical engagement of highV strength can be effected. l

As various embodiments may be made of the above invention and as changes mightV be made in the embodiment above set forth, it is to be understood that all matter hereinbefore set forth or shown in the accompanying drawing is tobe interpretedvas illustrative and not inl a limiting sense. I f

I claim: f

A connector for wire and the like which comprises: a'dihedral member of deadl soft, malleable sheet copper o r the like having parallel sides normal to thedihedral angle adapted to receive a hand wrench, and having a female opening through one of the angularly related portions thereof adapted to receive a collet; a collet having an opening therethrough adapted to lit over Vthe Wire or like member to which it is to be con@- nectedand having a smaller externally threaded end portion of substantially uniform external diameter tted into and extending through said female opening in a directionfaway from the 'other angularly related portion, Ythe opposite end lof said collet tapering to an external diameter substantially' largerlthan said female' opening and lto substantially 'increased wall thickness, the Walls of said tapering end -being Yslotted to permit its compression to smaller diameter but the width of the slots being limited to less than would permit said tapering end to be drawncompletely into the female opening, the interior surface of Ythe tapering end beingserrated for secure ver1- gagement with the wire, and the interior surface at thersmall'er end being'smooth and smoothly roundedy at its edge; and a'nut threaded onto said smaller en'd of the collet'and bearing against said female member whereby to draw said tapering end partially into the femaleA opening and thereby to reduce its internaldiameter by closing its slots.V Y y g STEPHEN N. BUCHANAN-- 

